The present invention relates to an actuator for an accelerator (hereinafter refereed to as an "actuator" simply), and more particularly, to an actuator for remotely controlling such a speed governor by automatically regulating a degree of opening to be used for a Diesel engine or the like, for example, in construction equipment. The actuator of the present invention can be utilized for various purposes such as for controlling a valve as well as an engine.
Conventionally, construction equipment such as a power shovel has a function of automatic deceleration or of programmed driving adapted for operations needed.
As shown in FIG. 8, an actuator 61 of a conventional type comprises a driving part 63 having an output pulley 62 and a control part 65 having a feed-back pulley 64 which are separately provided. For that reason, an engine speed governor 66 is provided with a small pulley 68 as well as an engine pulley 67. Numeral 69 denotes a motor, numeral 70 denotes an operation dial, and numeral 71 denotes a terminal board which connects to the operation dial 70. The output pulley 62 and the engine pulley 67 are connected each other by means of a control cable 72, on the other hand the feed-back pulley 64 and the small pulley 68 are connected each other by means of a feed-back cable 73. An electrode plate 74 is mounted on the feed-back pulley 64, and a terminal 75 for acceleration and a terminal 76 for deceleration are provided on the terminal board 72 and which are adapted to come into slidable contact with the electrode plate 74. Operation of the motor is effected via motor control means MC.
With the conventional actuator 61 thus arranged, when the operation dial 70 is turned to set to a certain angle, and if there is a deviation between the angle set by the operation dial 70 and the angle through which the feed-back pulley 64 rotates in response to the setting by the operation dial 70, the motor 69 revolves, responsive to an output signal corresponding to the deviation, in such a direction as to offset the deviation. Whereupon, the motor 69 causes, through the output pulley 62 and control cable 72, the engine pulley 67 to rotate. As the engine pulley 67 rotates, the rotation angle thereof is transmitted through the feed-back cable 73 to the feed-back pulley 64. Such an operation is continued until the deviation is nulled. Thus, opening of the speed governor is controlled so as to adjust the rotating speed of the engine to a desired value eventually.
As described above, the conventional actuator 61 for use in an acceleration control device comprises the driving part 63 and the control part 65 separately. Accordingly, it is difficult to down-scale the actuator 61, hence desired time and labor for mounting it on a machine body. This leads to an the increase in the production cost of the actuator.
The present invention has been attained to overcome such problems. Thus, it is an object of the present invention to provide a down-scaled and simplified actuator.